CVE-2026-48156

pypdf is a free and open-source pure-python PDF library. Prior to 6.12.0, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires cross-reference streams with /W [0 0 0] values and large /Size values. This vulnerability is fixed in 6.12.0.

CVSS 4.0

5.1CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS 3.1

3.3CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

EPSS

0.1% chance of exploitation in the next 30 days; higher than 2% of CVEs (scores of 2026-10-25)

CWE

CWE-834

Published

2026-05-28

Modified

2026-10-14

Record from

the NVD, synced 2026-10-19

Affected

• pypdf_project:pypdf

Packages (OSV)

References

• https://github.com/py-pdf/pypdf/pull/3791
• https://github.com/py-pdf/pypdf/releases/tag/6.12.0
• https://github.com/py-pdf/pypdf/security/advisories/GHSA-248m-82v9-q6g6

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